The present invention relates to office supplies and the invention relates more particularly to fasteners for securing a stack of documents or papers together by passing a pair of prongs through a spaced apart pair of holes near the top edge or side edge of each sheet of paper.
Known fasteners are typically referred to by a well know trademark of “Acco Fasteners.” Such fasteners have a horizontal lower piece with a pair of thin metal prongs which may be oriented vertically, and a top piece for securing the metal prongs. The papers are secured by laying the papers over the fastener wherein the prongs pass through spaced apart holes in the papers. Next, the top piece is placed over the prongs and over the stack of paper, and the prongs are bent over the top piece and affixed to the top piece to secure the papers in place. Large stack of papers fastened with the known “Acco Fasteners”, which typically utilize thin metal prongs, are notorious for becoming unfastened, and edges of the thin metal prongs are know to cuts fingers or hands if not carefully handled.
Because of the unreliability and possibility of cuts from the thin metal fasteners, attempts have been made to make fasteners which are fabricated from plastic. One such fastener is described in U.S. Pat. No. 5,096,323 for “Prong Type Stacked Paper Fastener,” which includes a pair of prongs which fit through openings in a top piece. The prongs include a series of longitudinally spaced apart holes therethrough, and the top piece includes locking tang means which engage the holes in the prongs. The prongs are then folded over and secured by slide locks on the top piece. Because the holes are spaced at discreet distances, the prongs can only be tightened in discreet steps, and therefore papers are often held loosely in such fasteners. Such loose holding of papers invites tearing and loss of papers.
U.S. Pat. No. 5,257,870 for “Paper retaining Means,” shows a paper fastener which has a pair of notched prongs which pass vertically through a top piece, and then bend to a horizontal attitude and are retained under first and second clipping parts. Because it is necessary to feed the prongs through a confined space under the clipping parts, releasing the prongs requires two fingers. Furthermore, once the prongs are under the clipping parts, they cannot readily be tightened.
U.S. Pat. No. 5,265,968 for “File Clip,” describes a fastener comprising a base component having two elongated flexible members extending therefrom. The members are flexible in a direction orthogonal to the base. Papers are slid over the members, and then the members are fed through apertures in a retaining component. Internal teeth in the retaining component engage teeth on the members to retain the members in the retaining component. The fastener of the '968 patent appears to be a very expensive to manufacture due to the number of details in the design, and not easy to manipulate. Further, the members appear to flap freely after insertion through the retaining component, thus frustrating stacking of fastened papers.